Table 1. Definition of tasks.

Task	Definition
Rest	After swallowing saliva, subjects assumed a relaxed facial position with the lips in repose and the teeth in light contact in the habitual maximum intercuspation position. Recording was made approximately 10 s after commencement of saliva swallowing.
Peak of the maximum smile	A grinning effort was made with the corners of the mouth pulled laterally and the cheeks elevated with maximal effort and with the teeth in the habitual maximum intercuspation position.